A panorama of what’s visible from that location, marking the position of peak geographic landmarks

A list of the peaks, and the ability to show their position relative to your location on Google Maps

Terrain profiles (elevation versus distance from the location to any point on the map)

A plot all the areas visible from that location in red on Google Maps (aka the “viewshed” or “weapons fan”)

Contour lines (zoom in for these)

Google Earth export of position, viewshed, horizon line and horizon extent. If the viewshed area is large, this might strain the memory capacity of lesser systems.

It uses 30-meter SRTM version 1 data for its calculations, so there may be some quirks depending on whether there are holes in the SRTM coverage for your area. They’re switching over to SRTM version 2 soon, which is better but still not perfect. It only works in the US right now, but according to OgleEarth, they hope to expand coverage worldwide. A cool site! Check the OgleEarth posting for more info.